<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    body  {
  -webkit-touch-callout: none; /* iOS Safari */
    -webkit-user-select: none; /* Safari */
     -khtml-user-select: none; /* Konqueror HTML */
       -moz-user-select: none; /* Firefox */
        -ms-user-select: none; /* Internet Explorer/Edge */
            user-select: none; /* Non-prefixed version, currently
                                  supported by Chrome and Opera */
}
#cal {
  width: 232px;
  background: #838383;
  margin: 10px;
  padding: 0;
  display: flex;
  flex-direction: row;
  flex-wrap: wrap;
  list-style: none;
  align-content: flex-start;
  border-width: 0 1px 0 0;
  border-style: solid;
  border-color: #838383;
/*   border-radius: 3px; */
  overflow: hidden;
}

#cal li {
  /* border: 1px solid black; */
  background: white;
  height: 48px;
  margin-left: 1px;
  margin-bottom: 1px;
  line-height: 48px;
  text-align: center;
  font-size: 20px;
  cursor: default;
}

#cal li.key:active {
  background: #a9a9a9;
}

#cal li.input {
  height: 80px;
  background: #979798;
  font-size: 36px;
  line-height: 110px;
  text-align: right;
  padding-right: 5px;
  color: white;
  font-family: "Shree Devanagari 714"
}

#cal li.func {
  background: #d0d0d0;
}

#cal li.operator {
  background: #f6872c;
  color: white;
}

#cal li.operator:active {
  background: #bd6821;
  color: #5d5d5d;
}

#cal li.num {
  background: #dcdcdc;
}

.size1 {
  flex: 1 21%;
}

.size2 {
  flex: 2 42%;
}

.size4{
  flex: 4 100%;
}
  </style>
</head>
<body>
  <ul id='cal'>
    <li class="size4 input">
      123450
    </li>
    <li class="size1 key func">C</li>
    <li class="size1 key func">±</li>
    <li class="size1 key func">％</li>
    <li class="size1 key operator">÷</li>
    <li class="size1 key num">7</li>
    <li class="size1 key num">8</li>
    <li class="size1 key num">9</li>
    <li class="size1 key operator">×</li>
    <li class="size1 key num">4</li>
    <li class="size1 key num">5</li>
    <li class="size1 key num">6</li>
    <li class="size1 key operator">-</li>
    <li class="size1 key num">3</li>
    <li class="size1 key num">2</li>
    <li class="size1 key num">1</li>
    <li class="size1 key operator">+</li>
    <li class="size2 key num">0</li>
    <li class="size1 key num">.</li>
    <li class="size1 key operator">=</li>

  </ul>
</body>
</html>